One about the rear brake?

[dickdastardly]

I recently had my brakes overhauled at a local garage. New seals, pads and the lot really. I also fitted a goodridge braided line and have the race type reservoir from Tyga. Anyway, after having it bled at the garage the brake went really soft and spongy really fast (the lever would stop at the exhaust and that's only because it was hitting it). I thought maybe some air had been trapped because the brake had been bled from dry. So I bled the brake again and it was sharp as.

Now to my point; once again the brake is getting soft and spongy and I don't know why. I've checked for leaks but didn't see any. One thing I have noticed is the reservoir has a oily kind of dew over it, like condensation but instead of water there's what I assume to brake fluid.

Help please

[alexwitham]

race type reservoir from Tyga...

Theres your problem...
Some guys on here could tell you exactly why, but i think its something to do with the material of the aftermarket reservoir that attracts water or something.

Go back to standard and the problem will probably be cured.

[greggo]

Hmm. I use one on my race bike and have no issues. Is it a something that only occurs if you use them on the road in all weathers?

Check the whole thing seals properly, you shouldn't get condensation inside (or not enough to affect brake performance) if it is sealed properly.

Have you also checked its not an issue at the caliper end, and you are not losing any pressure from leaking pistons?

[Cammo]

Yeah the hrc res pipe does sometimes seem to have some issues. I've seen this problem and have heard of many people that have had issues. The pipe apperars to be porous and the fluid can seep out. Most of these problems were happening a couple of years ago.

Given that many still use them successfully, maybe the material has been improved?

You could always just replace yours with a piece of standard brake hose and use the hrc end bung.

[tygapaul]

The hose is the same as it ever was. HRC use the same number and we sell roughly 1000 kits a year. The only negative comment we get from customers is that the moisture gets attracted to the outside of the tube. It also gets attracted to a glass of cold beer but that doesn't mean the beer is leaking out or the water diluting your precious brew. I am not a chemist and won't claim to know what the workings are but keep your bikes in your warm dry living room or bedrooms like I do and you won't even come across this phenomenon.

Anyway, this is on the outside and not the inside which is sealed. even assuming that the moisture was able to get into the hose area, this is not part of the actual braking circuit and only acts to top up the level. If the brake part of the between the master and the caliper is properly sealed, the amount of fluid entering from the hose to the master cylinder would be very miniscule and would only serve to top up the fluid in the system as the brake pads wear and the volume behind the piston increases. Now unless you have a very strange riding style, rear brake pads tend to last forever and so the amount of fluid entering from the hose would be tiny and the amount of compressible moisture (if it in fact actually got in the tube) would be a fraction of that so if your brakes are showing sponginess really fast it is much more likely air is in the system which is much more compressible than the alleged moisture.

By the way, we have tried many other tubes and they have never been as durable as the HRC one. If anybody has a good alternative, we'd love to hear from you.

[Cammo]

Very valid points!

Brake fluid is hygroscopic, and attracts moisture from the air. This suggests that the tube does have some oxygen transfer properties. This is not (largely) temperature related.

By the way, we have tried many other tubes and they have never been as durable as the HRC one. If anybody has a good alternative, we'd love to hear from you.

Err, regular Honda issue rubber brake hose?!


Just taking the piss, your points are all very good ones.

[bourney]

Maybe a screwed master cylinder?